This invention relates to a quick-release fueling coupling which is suitable, for example, for use in refueling racing automobiles and in other applications requiring rapid connection and disconnection of a liquid supply to a liquid receptacle. In particular, the invention relates to an improved fueling coupling of a similar type to that disclosed in the pending application of Ray E. Mingus and Ross M. Stuart for "Non-Latching, Dry-Break Fluid Coupling," Ser. No. 377,337 filed July 9, 1973, now U.S. Pat. No. 3,866,638 assigned to the same assignee as the present application.
In automobile racing, it is important to refuel very rapidly during pit stops and refueling is often performed using either dump cans or overhead fueling rigs. A dump can is a hand-held container of 8-12 gallon capacity having a funnel-like spout which is inverted and placed against the inlet of the automobile fuel tank. An overhead rig includes a flexible hose with an outlet pipe which is coupled manually to the inlet of the fuel tank. Using either of these systems, there is a problem of spillage of fuel which can occur when the spout of the dump can (or the outlet pipe of the overhead rig) is applied to the tank inlet and when it is subsequently removed.
The aforementioned application of Mingus et al discloses a dry-break coupling which can be rapidly connected and disconnected and which minimizes spillage of fuel. Such prior coupling includes a housing connected to the vehicle tank defining an open-ended passage in which is positioned a valve seat. A spring-loaded plunger is resiliently biased against the downstream side of the valve seat to close it. A probe, connected to the refueling source, is provided with a nose connected to the probe by a stem. A sliding sleeve surrounding the probe is resiliently biased into sealing contact with the nose to prevent fuel flow outwardly of the probe. During refueling, the probe is inserted into the passage whereupon the nose forces the plunger away from the valve seat while at the same time the end of the sleeve seats against the upstream side of the valve seat. Further inward motion of the probe, causing the nose to pass through the valve seat, unseats the nose from the sleeve so that fuel can flow through the probe and the valve seat into the receptacle.
Although such prior coupling has proved generally satisfactory, certain problems could be encountered from time to time. For example, after the nose has passed through the valve seat, it is in a position where it may become trapped or jammed against the downstream side of the valve seat if the probe is hurriedly withdrawn at a time when it is substantially out of axial alignment with the passage.
Another problem with the prior device could arise during withdrawal because the plunger seated on the downstream side of the valve seat at a time when the nose and adjacent portions of the sleeve were still seated on the end of the plunger and the upstream side of the valve seat, respectively, leaves no substantial void space between them. Such a condition, with atmospheric pressure acting on the opposite side of the probe, could create a suction lock between the coupling parts requiring a substantial outward pull (in the order of 75-100 pounds) to pull the probe out of the passage.